Digital printers have been developed to facilitate the application of graphics, text, and other indicia to flexible substrates, particularly textile materials used for garments such as T-shirts, sweatshirts, and various other garments or textile products wherein inks or other printing materials are applied directly to the substrate. In conventional digital printing systems, the textile substrate is supported on a platen that is moved by a print transport system beneath a print head assembly for the application of inks or pretreatment liquids to one or more portions of the substrate. To prevent the substrate from inadvertent unwanted movement on the platen, various securing mechanisms have been employed such as clamps, edge frames, and tacky surfaces. These conventional securing systems are generally cumbersome to use and are not well suited for accommodating substrates or even printable areas of varying size. A need exists for improved methods and apparatus for securing textile substrates to printer platens that overcome these and other drawbacks of the prior art.